The invention relates to methods for three-dimensional image representation on a large-screen projection surface using a laser projector.
There are various embodiments of television projectors that can project an image onto a large-screen projection surface. One of these concerns laser projectors. A laser projector can be used for a two-dimensional representation of graphics, etc. For example, in a color laser projector light of the colors red, green and blue is produced by three lasers. The light beams are deflected horizontally by a rotating polygonal mirror. The horizontal deflection permits the representation of a display screen line. After the horizontal deflection, a vertical deflection takes place by means of a further rotating mirror. In this way, the image is projected on a large-screen projection surface via an optical unit. A laser projector thus enables the representation of very large images with particularly brilliant colors.
A color laser projector comprises three lasers for the colors red, green and blue, but the laser design is the same for all three colors. For an individual image point on the large-screen projection surface, the different colors are merely superimposed on one another for a correspondingly required overall color.
Among laser projectors, there are two different basic types. One type operates with multimode lasers and the other type operates with monomode lasers. The laser beams produced by monomode lasers comprise a single direction of polarization.
They have a light polarized in linear fashion. In contrast, the laser beams produced by multimode lasers have circularly polarized light; i.e., they have more than just one direction of polarization. For example, they have 2, 4, etc., different directions of polarization. In the extreme case, their polarizations scatter in all directions.
The principle of laser display technique is described in the German publication Funkschau, 1995, no. 18, pp. 104-107, under the column Technik and the title "Die Laser-Display-Technik," and in a sales brochure, published at the CeBIT 1995, of the company Laser Display Technologie GmbH & Co. KG, Carl-Zeiss-Str. 2, 07552 Gera. In addition, from the German laid open publication DE 32 14 327 Al it is known to occupy a display screen in line-by-line exchange with polarization film strips of alternating directions of polarization, so that a stereo field can be reproduced per television field.
From the references EP-A-0 211 596 and JP-A-59/176 720, methods are known for large-screen projectors with which three-dimensional images can be represented. Polygonal mirrors are thereby used on whose mirror parts a laser beam impinges in frontal fashion.
From the reference DE-A-41 25 241, a method for large-screen projectors is likewise known with which three-dimensional images can be represented. In this method, a polygonal mirror is not used.